2
\$\begingroup\$

teh element
I am trying to repair a remote from a car lock. The symptoms are that a red led is lit longer than usual after button press and no respond from car lock. It works sometimes. The battery and microswitches are replaced. All elements are resoldered. On the other side of the board is a tantalum capacitor. I measured it and is ok. (1uF 106)

What is this element on the right? It has 1Ω resistance

EDIT:
I desoldered the similar looking element which on the picture is still soldered. It says 560J and is totally short: 0Ω.

On the other side of the board is a capacitor similar looking but with a bar on the positive pole. The capacitor has 106 marking and is working.

\$\endgroup\$
  • \$\begingroup\$ Is it a shorted capacitor? \$\endgroup\$ – drzymala Apr 10 '13 at 3:46
  • \$\begingroup\$ If you reverse the probes when you measure the resistance, do you still get 1Ω ? \$\endgroup\$ – Nick Alexeev Apr 10 '13 at 3:48
  • \$\begingroup\$ Yes. And my cables are .1Ω So really it should be .9Ω \$\endgroup\$ – drzymala Apr 10 '13 at 3:50
4
\$\begingroup\$

If this were a capacitor, I'd say by the shape and size that it have to be tantalum. However, tantalum caps are polarized, and this device is not. Ergo, not likely a cap.

The triangular marking at the top of the device resembles the Epcos logo:

enter image description here

A quick check of Epcos shows me that they have a line of SM inductors which closely resemble your part, in both shape and markings.

enter image description here

This data sheet says that the line 331K represents the inductance and the bottom line is a date code.

This note explains the code in more detail: K is a tolerance code (+/- 10%), and depending on the size of the part, the inductance is in either microhenries or nanohenries. I don't think your part is actually 330 microhenries given its size.

I think you have a 330nH EPCOS SM inductor. QED

\$\endgroup\$
  • \$\begingroup\$ Thank you for your thorough answer. It is the first time I saw a inductor like this. Thank you for your time and effort \$\endgroup\$ – drzymala Apr 13 '13 at 22:21
2
\$\begingroup\$

Hypothesis: these are SMT inductors.

It fits the observations. Inductor has a low DC resistance. Inductor doesn't require a polarization bar on the package.

Inductors like that do exist: SP1008R-331K, 1008-560J

\$\endgroup\$
  • \$\begingroup\$ Thank you for your answer Nick. Your answer is perfectly valid, but @Madmanguruman got more votes, so I accepted his answer. I really appreciate your engagement in this thread. \$\endgroup\$ – drzymala Apr 13 '13 at 22:25
2
\$\begingroup\$

I have a similar device marked as : 331K and 9421 below, it is located in the power surge stage, before the protection diodes, so is almost sure that this device is a coil, it measures approx 2 Ohms. I found similar devices in another part of the circuit with the same value.

\$\endgroup\$
1
\$\begingroup\$

You’re probably right that it’s a capacitor. 331K would stand for 330pf.

Edit: Upon further discussion, I’ve changed my opinion. @Passerby makes a good point that the elements are kind of large, and the fact that both of them have low resistance also argues against capacitors, as @Nick Alexeev points out (One of them could probably be a shortened capacitor, but both of them is less plausible).

\$\endgroup\$
  • \$\begingroup\$ How confident are you that this really is a shortened capacitor? \$\endgroup\$ – drzymala Apr 10 '13 at 3:53
  • \$\begingroup\$ @martini "How confident", eh? "How confident" are you that this is not a capacitor? If you have doubts, provide the detailed doubts. \$\endgroup\$ – Nick Alexeev Apr 10 '13 at 4:01
  • \$\begingroup\$ I’m not the world’s foremost expert on capacitors, but the labeling and form factor certainly make it plausible, cf this capacitor \$\endgroup\$ – microtherion Apr 10 '13 at 4:04
  • \$\begingroup\$ @NickAlexeev The capacitors usually have the polarity marking (a red bar) on one of their side. I just want a clear answer from someone who saw such a capacitor without a bar saying: Yes, Martin or NO! this is a inductor! \$\endgroup\$ – drzymala Apr 10 '13 at 4:05
  • \$\begingroup\$ I wouldn’t expect such a small capacitor to be polarized, so the absence of a polarity marking would hardly be surprising. \$\endgroup\$ – microtherion Apr 10 '13 at 4:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.